1. Field of the Invention
This invention is directed to novel multifunctional ashless dispersants derived from Mannich reaction of alkyl or alkenyl succinimides, dimercaptothiadiazoles and carbonyl compounds and to lubricant compositions containing same.
2. Description of Related Art
Alkyl- or alkenylsuccinimides are well known in the art as ashless dispersants for lubricants and fuels. Their principal function in such applications is to prevent the deleterious sludge accumulation on engine parts. Because of today's hotter and faster running engines, the performance properties of ashless dispersants are being optimized to cope with the increased sludge formation resulting from enhanced thermal and oxidative degradation of lubricant formulations. The synergistic combination of the succinimide and the sulfur, nitrogen-containing heterocyclic dimercaptothiadiazole functionalities in the products of this invention provides ashless dispersants with additional multifunctional antioxidant, antiwear and potential metal passivator protection for lubricant compositions.